Dam's Threat to Rain Forest Spurs Quarrels in the Amazon

By MARLISE SIMONS, Special to the New York Times

Published: September 6, 1987

RIO DE JANEIRO, Sept. 5—
A giant new dam in the middle of the Amazon rain forest is about to flood millions of trees and animals, even though energy and environment experts say it should never have been built.

Now, with the rising of the waters only seven weeks away, Government agencies are quarreling fiercely over the dam.

Although one of the colossal gates has already been sealed, two agencies dealing with environmental issues have demanded that operations be slowed to insure that the floods will cause less havoc. One agency, the Government's Center for Amazon Development in Manaus, has said it is holding up the operating license until it receives assurances that a sizable number of the forest animals will be saved.

The center has also called for assistance from abroad to rescue and eventually to harbor animals. The region is said to be teeming with monkeys, agoutis, jaguars, birds and reptiles among countless others. Rush to Develop Wilderness

''It is a huge area of living tropical forest and the impact of the water will be devastating,'' said Lydia Loreiro da Cruz, a director of the center. ''We would accept requests from research institutions and zoos abroad that want to get involved.''

Set, in the heart of the Amazon basin, the Balbina hydroelectric dam will harness the Uatuma River, an affluent of the Amazon, and send its energy to Manaus, 90 miles to the south. It was ordered more than a decade ago by the military regime then in power, which saw the dam as a vital pivot in its rush to develop Brazil's vast tropical wilderness.

But today, after years of delay and expenses of $600 million, it is lamented as another of the overly ambitious projects on which the military spent much money and land. Other multimillion-dollar projects that have not worked out include the Transamazonian Highway and a series of nuclear plants.

Government energy experts have said that the cost of the Balbina dam is out of proportion to the little energy it will yield. The new Tucurui dam, which has flooded a similar area in the Eastern Amazon, can produce 15 times as much electricity. An official of Electronorte, the state-owned electric company, said that today, the Balbina dam would probably not be built since its energy output was inadequate and the impact of flooding such a large area was not known. Oil Bill To Be Halved

Environmentalists have protested the building of a hydroelectric project in a region as flat as this. They say that to amass enough water to drive the generators, the flooded area must be unusually large. The dam will inundate close to 600 square miles, about half the size of Long Island, for its small production capacity of 250 megawatts. For a project like this, ''it's the biggest puddle I've ever heard of,'' said Thomas Lovejoy, a senior official of the World Wildlife Fund who recently visited Manaus. Even at this size, the dam will fill only half of Manaus's energy needs. A future phase could flood another 300 square miles.

One argument for the dam, energy experts say, is that it will halve Manaus's oil bill. This old trading post on the Amazon bank has rapidly expanded into a city of one million people since the former military regime turned it into a duty-free zone for assembly plants. But cut off from the world by thousands of miles of jungle, Manaus's energy bill is four times higher than that of comparably sized cities. The 8,000 barrels of oil it uses daily must be hauled all the way along the Amazon river to a local refinery that has become inadequate.

Because of the debate over the Balbina dam, Government energy officials are also reviewing the entire Amazon energy plan. In different spots, away from the center of the basin, three large new dams have already been built, two are nearly finished and at least another three are on the drawing board.

But as long as the rush on the region continues - many Amazonian towns grow by 15 percent a year - energy and environment experts agree there are no easy answers to the energy needs. Balance Is Easily Disturbed

Part of the problem is that the world's largest fresh water system offers few good dam sites. Much of the huge grid of rivers runs through areas with little downward slope and many ecologists say dam building provides one more example of how easily the delicate balance of Amazon nature is disturbed.

''Good places for dams are rare and almost inaccessible,'' said an Electronorte official. ''If we put a dam in the Amazon at Obidos, we would flood Manaus,'' 300 miles away.

Critics of the Balbina dam at the Amazon Development Center say they are trying to make the best of a bad thing. ''The dam is built, this is a fait accompli,'' said Ms. Loreiro da Cruz. ''We can only try and reduce the damage.''

Two small Indian tribes in the forest, totaling 107 people, have received new lands and have been promised compensation in the form of medical assistance and education for the next 25 years. More Animals May Be Saved

The Development Center and the Federal Department for the Environment are demanding that at least the most valuable trees in the area be cut and put to some use.

''We have asked for bids on the wood, but no one one has shown any interest,'' said a spokesman at Electronorte.

The environmental agencies also say they want far more animals saved than planned by Electronorte, which they say allows only for rescuing the small percentage needed for scientific research. ''We want much more than that,'' said Ms. Loreira da Cruz.

Electronorte responds that it has built tanks to save and study dolphins, manatees and otters, animals whose numbers have been dwindling dramatically in recent years. ''The flooding will be very slow,'' a spokesman said. ''We think that many land animals will be able to flee.''